The present invention relates to a unit for mounting a free arm sewing machine in a work cabinet and in particular to a unit whereby the machine is selectively supported in two work positions, one wherein the free arm is disposed above the cabinet work surface and the other wherein the free arm is flush with the work surface, and a storage position in which the entire sewing machine is contained within the cabinet beneath the work surface in a space efficient manner.
A free arm sewing machine is generally employed for sewing garments having a generally tubular configuration, such as trouser legs, sleeves, socks and the like. In use, the garment is slipped over the free arm, which is positioned above the bed or base of the machine.
A sewing machine of this type may also be used in the same fashion as a conventional flatbed machine wherein the needle plate is at the same level as the work surface of the cabinet. In order for the machine to assume this position, either the machine must be lowered or the work surface raised so that the upper surface of the free arm is substantially flush with the work surface of the cabinet. Since the free arm is narrower and shorter than the cabinet opening, wood inserts or the like are customarily positioned between it and the sides of the cabinet opening. This provides a continuous work surface flush with the needle plate and the machine may be utilized in the same manner as a conventional flatbed machine.
A conventional feature in sewing machine cabinets is a mechanism whereby the machine may be dropped to a lower storage position thereby enabling a hinged cover to be folded over the opening in the cabinet work surface. It is desirable for the machine to be rotated to a horizontal position when it is stored, as this normally results in greater economy of space.
Although mounting assemblies for supporting a free arm sewing machine in the storage position and two work positions described above are known they are often quite complex and difficult to operate. One prior art mounting unit disclosed in U.S. Pat. No. 4,005,918, comprises a pair of hinged members, one of which is mounted for pivotal movement within the cabinet. In the lower work position, the members are folded together parallel to and below the working surface of the cabinet. In the upper work position, wherein the free arm is completely exposed, one member is flush with the top of the cabinet while the other is angularly disposed between its pivotal mounting and the hinged connection with the upper member.
In U.S. Pat. No. Re. 28,835, the free arm machine cabinet includes a hingedly connected drop shelf and means for supporting the shelf parallel to and beneath the upper work surface of the cabinet. The drop shelf carries a mount for the machine and by means of linkage, permits raising and lowering of the machine to upper and lower work positions. This linkage includes a pivotally fulcrumed lever on the drop shelf having a work arm which underlies the machine mount so as to raise and lower the machine when the other arm of the lever is manually operated. The hinged connection for the shelf permits it to be dropped to its storage position.
One prior art free arm cabinet presently on the market comprises a first pair of pivot arms pivotally secured to the back of the cabinet and the machine mounting bracket, and a second pair of pivot arms positioned respectively above the first arms and pivotally secured to the back of the cabinet and the mounting bracket. The machine is supported on the pivot arms in two use positions and a storage position. In the storage position, however, the machine is inclined upwardly from the horizontal so that it occupies approximately 15 in. of depth as opposed to the present invention wherein the required storage depth is no greater than the width of the supporting platform, e.g. approximately 7 in.
Other examples of prior art mounting arrangements for free arm sewing machines include U.S. Pat. Nos. 3,993,008 and 3,468,589, wherein the machine is mounted for rectilinear movement on vertical tracks. In U.S. Pat. No. 3,918,780, a complicated gear train is utilized to move the machine between the various positions.
The present invention overcomes the disadvantages of the prior art by providing an extremely simple arrangement whereby the free arm sewing machine may be supported in upper and lower use positions wherein the upper surface of the free arm is disposed respectively above and flush with the work surface of the cabinet, and in a storage position within the cabinet wherein the machine is rotated to a horizontal position just beneath the cabinet work surface.
This is accomplished by means of a pair of pivot arms which are pivotally secured to the cabinet and hingedly connected to the machine mounting platform. In the storage position, the mounting platform is rotated to a vertical position such that the machine lies horizontally within the cabinet. The base of the machine is forced upwardly against the top of the storage compartment due to the fact that the center of gravity is forward of the cabinet mounting points for the pivot arms. This is also advantageous from the standpoint that part of the machine is dropping during the initial movement out of the storage position thereby partially counterbalancing the weight of the machine. In the lower use position, the platform is rotated to a horizontal position parallel to and beneath the work surface of the cabinet and the segments of the front pivot arms which extend between the cabinet pivots and the platform hinges are supported on a stop which is mounted to the opposite side walls of the cabinet. In the upper use position, the mounting platform is supported on the conventional cabinet flip board and the rear pivot arm which urges the platform forwardly against the flip board.
In order to clear the stops when dropping the machine from the lower use position to the storage position, the machine and platform are tilted forwardly thereby urging the pivot arms to positions which are mutually coplanar. This causes the arms to bind and pulls the side portions of the forward arm inwardly over the stops and permits the entire assembly to drop downwardly past the stops. In order to enable the sides of the forward arm to be pulled inwardly, the ends thereof are mounted for axial sliding movement.
Specifically, the present invention contemplates a cabinet mounting unit for free arm sewing machines comprising: a platform or other means for attaching the machine, a first pivot arm connected to the cabinet and to the platform, a second pivot arm piovtally connected to the cabinet and platform and having a plane of rotation, first means for supporting the platform and pivot arms whereby the platform occupies an upper work position parallel to the cabinet work surface, second means for supporting the platform and pivot arms whereby the platform occupies a lower work position parallel to the cabinet work surface and below the aforesaid upper position, the second means including a stop mounted to the cabinet and being within the second arm plane of rotation, the stop being engaged by the second pivot arms and supporting it and the platform against gravity, and third means for pulling the second pivot arm inwardly out of plane of rotation so that the second pivot arm clears the stop and is free to drop downwardly past the stop together with the platform to a storage position.
It is an object of the present invention to provide a cabinet mounting unit for free arm sewing machines wherein the machine is selectively supported in an upper use position with the free arm disposed above the cabinet work surface, in a lower use position werein the top surface of the free arm is flush with the cabinet surface, and a storage position wherein the entire machine is disposed beneath the cabinet surface and in a horizontal position.
Another object of the present invention is to provide a cabinet mounting unit for free arm sewing machines which is of simple and efficient construction thereby minimixing manufacturing costs and increasing reliability.
A further object of the present invention is to provide a cabinet mounting unit for free arm sewing machines requiring no more space for storage than conventional flatbed machines.
A still further object of the present invention is to provide a cabinet mounting unit for free arm sewing machines wherein the machine is capable of being shifted between storage and upper and lower use positions quickly and with a minimum of effort.
Yet another object of the present invention is to provide a free arm mounting unit which can be easily installed in existing flatbed sewing machine cabinets.